Search results for "Genetic erosion"
showing 10 items of 16 documents
Olive Growing in a Time of Change: From Empiricism to Genomics
2016
Since its beginning, the olive crop has been a long-lived agricultural system in the Mediterranean Basin being well adapted to this area. Traditional olive growing, still prevalent in most producing areas, is characterized by low tree density and rainfed orchards with low yield and manually harvested. The traditional olive growing technology is local, diverse, and empirically based. New high density, irrigated, and mechanically harvested orchards has been progressively planted since the end of World War II. These plantations produce high crops at low costs, but they reduce the diversity of cultivars, increase the demand of inputs and the risk of environment unbalances. The expansion and int…
Spatio-temporal dynamics of genetic variation in the Iberian lynx along its path to extinction reconstructed with ancient DNA
2017
here is the tendency to assume that endangered species have been both genetically and demographically healthier in the past, so that any genetic erosion observed today was caused by their recent decline. The Iberian lynx (Lynx pardinus) suffered a dramatic and continuous decline during the 20th century, and now shows extremely low genome- and species-wide genetic diversity among other signs of genomic erosion. We analyze ancient (N = 10), historical (N = 245), and contemporary (N = 172) samples with microsatellite and mitogenome data to reconstruct the species' demography and investigate patterns of genetic variation across space and time. Iberian lynx populations transitioned from low but …
Urgent need for preservation of grapevine (Vitis vinifera L. Subsp. vinifera) germplasm from small circum-Sicilian islands as revealed by SSR markers…
2016
Since the last decades grapevine germplasm is undergoing a process of rapid genetic erosion. This process is of particular concern in minor circum-Sicilian islands, because of the sharp reduction of the cultivated surfaces and the shift of their economy from agriculture to tourism. Aiming at valorising and preserving the surviving varieties we collected 185 accessions during several surveys since 2007. Six nuclear microsatellite markers were used for germplasm characterization, yielding 75 different genetic profiles. We found out that most genetic profiles (39) were not listed in national and international grapevine databases, confirming that the Sicilian minor islands represent underexplor…
Patterns of genetic variability and habitat occupancy in Crepis triasii (Asteraceae) at different spatial scales: insights on evolutionary processes …
2012
International audience; Background and Aims Archipelagos are unique systems for studying evolutionary processes promoting diversification and speciation. The islands of the Mediterranean basin are major areas of plant richness, including a high proportion of narrow endemics. Many endemic plants are currently found in rocky habitats, showing varying patterns of habitat occupancy at different spatial scales throughout their range. The aim of the present study was to understand the impact of varying patterns of population distribution on genetic diversity and structure to shed light on demographic and evolutionary processes leading to population diversification in Crepis triasii, an endemic pl…
Crocus sativus L. Ecotypes from Mediterranean Countries: Phenological, Morpho-Productive, Qualitative and Genetic Traits
2021
The characterization of C. sativus ecotypes is of great interest for preserving them from a possible genetic erosion due to the decrease of European cultivation surface. In this study, we evaluated four ecotypes from Italy (Sardinia and Abruzzo), Spain (Castilla-La Mancha), and Greece (Kozani) in order to detect the existence of variability and promote the biodiversity of this crop. Thirty-one traits related to saffron flowering, flower morphology, production of spice and daughter corms, vegetative development (leaf and corm traits), and spice quality, were evaluated. In addition, a genetic analysis through three PCR-based approaches, SSRs, RAPD, and SRAP was assessed. Results highlighted a…
Soil genetic erosion: New conceptual developments in soil security
2019
In the last decades, in some Mediterranean areas, pedodiversity decreased mainly due to pedotechnique application in large-scale farming that transformed original soils into Anthrosols. Supporting the consideration that soils can be considered as living systems, the original concept of 'soil genetic erosion' is re-proposed. Data, extrapolated and modeled from a Soil Information System in a study case representative of a Mediterranean landscape, predicted that most of the soil types would disappear in few years leading to a decrease of the soil diversity and originating soil genetic erosion. This circumstance is intentionally here told in form of a story where the fairy tale characters are s…
Genetic diversity in Cytisus aeolicus Guss. (Leguminosae), a rare endemite of the Italian flora
1998
ABSTRACT Cytisus aeolicus Guss, is an endemic plant restricted to the isles of Vulcano, Stromboli and Alicudi in the Aeolian archipelago. All known populations were assayed for genetic variability using enzyme polymorphism. Allozyme variation at 16 loci coding for 10 enzyme systems was examined. The great majority of loci turned out to be monomorphic or fixed heterozygous. The observed genetic depauperation is indicative of historical factors, such as the bottleneck effect associated with migration, and the founder effect in population re-establishment. The low genetic diversity is largely partitioned within rather than among populations, indicating that extant populations have not been est…
Changes in the genetic diversity of barley of Nordic and Baltic origin, studied by isozyme electrophoresis
2003
AbstractIn this study an evaluation was made of changes in the genetic variation of barley (Hordeum vulgare L.) of Nordic and Baltic origin, from the end of the 19th century until today. A comparison of Nordic and Baltic material with exotic material that has not been subjected to intense selection was also made. A total of 293 accessions, including 160 Nordic and 80 Baltic landraces, cultivars and breeding lines, and another 53 landraces of exotic origin (Central Asia), were surveyed using isozyme starch gel electrophoresis. For the four isozymes studied, 28 alleles at 11 loci were observed. The average total genetic diversity value (HT) for individual loci ranged between 0 and 0.519. In t…
Genetic variation of an Italian long shelf-life tomato (Solanum lycopersicon L.) collection by using SSR and morphological fruit traits
2014
The recovery of ancient germplasm in tomato (Solanum lycopersicon L.) has become necessary to limit the wide genetic erosion caused by the employment of modern cultivars. Among germplasm collections, long shelf-life landraces could represent an important source of biodiversity. The present study provides a first set of molecular and phenotypic data on long shelf-life (so called "da serbo" in southern Italy) tomato collection, mainly originated from Sicily together with some landraces from Campania and Apulia. The analysis of fruit traits showed a low intra-varietal variation, while exhibiting a quite higher inter-varietal variability. Overall, the cultivars have been classified in six fruit…
BIODIVERSITY OF SICILIAN FRUIT TREES: STUDIES ON PLUMS
2010
The Sicilian territory contains a wide reserve of biodiversity of fruit tree species that, over a period of several centuries, have found there propitious pedoclimatic conditions for their establishment, and genetic diversification. The indigenous germplasm characterized Sicilian agriculture until less than one century ago but, after the diffusion of new cultivars originating from genetic improvement programs, a great part of this germplasm was replaced and now these important resources are at high risk of genetic erosion. Recently, public interest in the safeguarding of biodiversity and the development of a new interest in genetic resources and their scientific, economic and cultural impor…